"Hot Zone" Rescue

A primary consideration of responders to hazardous materials incidents, as in all emergency operations, is rescue. Evolutions in hazmat team training scenarios typically involve the rescue of victims of an incident but what about the responders who wear chemical protective clothing (CPC) while operating in the chemical incident "hot zone" and become victims themselves?

Before the rescue of hazmat team members can begin, several questions must be addressed. Is the responder down due to unforeseen hazards, physical injury, cardiovascular compromise, heat stress, chemical contamination or equipment failure? Can the team member be assisted from the accident area or is the assistance of the backup crew necessary? What equipment will be needed to effect the rescue? The hazmat team must evaluate all of these factors.

Causes Of Responder Collapse

Responder health-related causes. A primary cause of collapse while wearing CPC is heat stress, primarily due to the body's inability to adequately dissipate heat while in CPC. Factors include the inability to evaporate sweat from the skin to the humid, stagnant atmosphere inside the CPC; the generation of heat from the responder's muscle exertion; the weight of the CPC; and air warmed by the lungs leaving the exhalation valve on open circuit self-contained breathing apparatus (SCBA).

Photo by Kevin W. Johnson
A backup team takes a specially designed rescue litter into the "hot zone" to assist in the rescue of a responder who has tripped and injured his lower right leg. He is wearing Level A protective clothing and is unable to walk.

Prevention is key to avoiding heat stress injuries. Pre-hydration of personnel with 13-16 ounces of water before entry is helpful; however, the main consideration is limiting the time of entry.

Cool vests or cooling suits are useful from the standpoint of improving conductive cooling but this comprises only a small percentage of the body's ability to transfer heat. These devices make the time in CPC more tolerable but caution should be exercised in using these devices as a tool to extend the work time of the entry team. The core temperature of the responder will rise in spite of the cooling device, once again due to the humid, stagnant air in the suit not allowing efficient evaporation of sweat from the body. In-suit-air flow systems assist the body's ability to use evaporation as a cooling mechanism but have the inherent disadvantage of increased air consumption, and are normally only considered as practical when utilizing a supplied air source.

The heat stress injury may manifest itself in one or more of the following conditions, listed in increasing order of severity: heat cramps, a brief, intermittent muscular cramping, typically in those muscles which are fatigued by heavy work; heat edema, swelling of the feet and ankles; heat syncope, a temporary loss of consciousness caused basically by the dilatation of blood vessels near the surface of the skin, resulting in reduced available vascular blood volume and a drop in perfusion to the brain, causing an unconscious state; heat exhaustion, which is characterized by weakness, fatigue, impaired judgement, vertigo, nausea and vomiting caused by loss of water or salt; and heat stroke, a failure of the body's thermal regulation systems to meet the demands of the heat stress, with symptoms including weakness, dizziness, disorientation, nausea, vomiting, loss of muscle control and psychiatric symptoms. The onset of heat stress while operating in CPC during hot zone entry could result in the inability of the responder to exit safely to the "warm zone" and the decontamination corridor.

Other causes of responder collapse include trips and falls, a possibility compounded by decreased visibility for wearers of CPC. These falls can result in fractures, blunt traumatic injury to the chest or abdomen, head trauma or other injuries.

Many medical conditions can cause unconsciousness or incapacitate the responder, including heart attack or other cardiovascular disease such as stroke, diabetes-related conditions such as hypoglycemia (low blood glucose) or diabetic ketoacidosis (elevated blood glucose), and anaphylaxis (allergic reaction) from such sources as insect stings prior to suiting up resulting in airway compromise. Prevention of these conditions depends on a sound medical program, in the form of at least biannual physical exams and on-site medical surveillance. On-site medical surveillance can catch such potentially life-threatening conditions as hypertension (high blood pressure), rapid or irregular heart rates, and neurologic deficit from prescription drugs.

Photo by Kevin W. Johnson
A fellow responder assesses the condition of the injured man.

Non-chemical hazards. These include such external causes as thermal injury from flash fire or heated chemicals, blunt trauma from explosion concussions, penetrating trauma from shrapnel thrown by explosions, electrocution from energized power lines or other exposed circuitry, trauma or entrapment from falling debris. Prevention depends on safety management, with an emphasis on elimination of these hazards before entry.

Chemical hazards. These represent a small percentage of the injuries to responders. Assuming that responders were wearing CPC, the exposure of responders to chemicals can present itself in two basic forms.

The first method is by chemical permeation of the CPC. This occurs on a molecular level, and is the actual passage of a chemical through a suit over a period of time1. Permeation prior to the time frame indicated in the chemical compatibility chart supplied by the suit manufacturer indicates either the accidental selection of the improper suit, premature failure of suit material or the presence of a chemical other than what was initially suspected.

The second method is via a mechanical breach of the suit. This involves a physical opening in the suit which allows chemicals to pass to the interior of the suit. One form of mechanical breach is penetration, or the movement of chemicals through zippers, seams or holes in the suit. Penetration can also occur from tears in the suit material from site hazards. Another form of mechanical breach is degradation, or the physical destruction of the suit material from use or ambient conditions.

Once CPC has been breached by chemical or mechanical methods, the effects of the chemical on the responder will vary according to the chemical involved, concentration and the rate of exposure via dermal routes. Consideration must also be given to the potential for exposure via inhalation routes if the SCBA mask or pressure hoses are compromised.

Preparation For Rescue

Recognition of the situation. Once a responder has fallen inside the hot zone, the incident commander's immediate concerns obviously turn toward the rescue of that responder. However the incident commander (IC) must resist the urge to immediately send the backup crews into the hot zone to effect the rescue, lest they become part of the problem as well.

Photo by Kevin W. Johnson
The backup team exits the area with the injured responder. Note the position on the rescue litter due to the self-contained breathing apparatus (SCBA) and low-pressure hose.

The IC's first, best source of information may be the fallen responder's own assessment, assuming his communications system is functional and the responder is physically able to communicate. The use of intrinsically safe communication systems is paramount in the scenario of a suit breech which allows combustible gases into the proximity of the responder. The responder's buddy can also give his or her assessment of the situation to assist the IC with the decision on a rescue attempt.

Chemical exposure collapse. If the reason for exposure was an obvious mechanical breach in the responder's suit, the IC should send in the backup crew to rescue the responder, advising both the backup crew and the remaining initial responder to use caution not to repeat the event which caused the fallen responder's suit breach.

If there is no obvious evidence of mechanical breach to the suit, the IC must assume there has been chemical permeation. The IC should advise the remaining responder to exit the hot zone if he or she cannot perform an immediate rescue of his or her buddy.

The rescue of personnel wearing CPC is extremely difficult even with the assistance of the backup team, and the IC must weigh the risks of losing a second responder due to chemical exposure. The IC should re-evaluate the potential chemicals involved, re-evaluate the CPC being used and, if an appropriate suit selection can be made, the backup team should don that CPC and enter the hot zone for a rescue. The IC may take into consideration the time factor involved prior to suit failure and initiate a rescue attempt based on this information.

If the chemical cannot be identified, the appropriate suit is not available and the suit failure was relatively early in the operation, the IC must resist the urge to immediately send in the backup crew, and must reassess the situation before any rescue effort is made in order to maximize the safety of the rescuers. Tremendous restraint on behalf of the IC must be shown, as this will be a difficult and unpopular decision.

Non-chemical hazard collapse. If the responder has fallen from a non-chemical hazard such as flash fire or electrocution in the hot zone, the IC should take steps to eliminate or isolate the hazard. This action will vary according to the situation but may include such operations as opening pre-staged fire protection lines or laying down additional foam. The IC should then send in the backup team to perform the rescue.

Responder health-related collapse. If the responder is down due to a health-related illness or injury, the IC should immediately take steps to send in the back up team, as the responder's buddy begins to assess the severity of his/her partner's condition.

Unfortunately, the CPC that protects the responder from chemical hazards tremendously restricts the rescuer's ability to accurately assess the fallen responder's medical status. Initial patient assessment should concentrate on one issue can the responder maintain his or her airway, breathing and perfusion until arrival at the established decontamination corridor at the edge of the hot zone or will basic life support (BLS) intervention be necessary prior to arrival at the established decontamination line?

First, the rescuer should attempt to establish verbal contact with the fallen responder. If successful, the rescuer has established responsiveness and the presence of an airway; however, the patency of the airway is not guaranteed. Also, the responder's mental status may be established at this time based on verbal responses.

The rescuer should carefully listen to his or her buddy's SCBA regulator operation, counting the respiratory rate of the fallen responder. If the respirations are absent or agonal (less than 10 a minute) or above 30 a minute, there is reason to suspect a life-threatening situation.

If the rescuers suspect a life-threatening condition exists, they must remove the fallen responder from the immediate chemical hazard area. In the absence of a formal decontamination corridor in the immediate area, the rescuers may need to perform a "hasty" decon.

The hasty decon is centered on accessing the responder's CPC with a effort to control gross secondary contamination. This procedure is to be done only in the case of a life-threatening condition in which the potential risk of secondary chemical contamination of the responder is outweighed by the need for immediate BLS intervention to save the responder's life. The skills available to the rescuers are limited primarily to the maintenance of a patent airway via the jaw thrust technique and the control of any gross hemorrhage; however, the opening of the fallen responder's CPC may reduce the heat stress and aid in perfusion by causing peripheral vasoconstriction, therefore increasing the blood pressure and available blood supply to the brain.

The decision to perform a hasty decon must be weighed carefully by the IC, with the knowledge that inadequate oxygen perfusion to the brain may result in the onset of brain cell death in four to six minutes.

Hasty decon procedures can be developed to local standards but ideally the hasty decon would use any fire protection lines near the chemical hazard area to spray off gross chemical contamination and opening the fallen responder's CPC utilizing the sterile technique method familiar to medical personnel removing gloves the suit is "peeled" from the responder, keeping exposure limited to the interior surfaces of his or her suit. If the fallen responder's original buddy has chemical contamination on the gloves of his or her suit, care must be taken not to touch his or her partner directly after the suit is opened.

Once the suit is open, the responder is taken to the decon corridor at the edge of the hot zone with the SCBA in place. Total removal of the CPC at this point may prove impractical and unnecessary. During transit to decon, the responder's airway should be monitored for patency. The use of further airway adjuncts would involve removal of the SCBA and the potential exposure of the responder via inhalation.

In the scenario that the fallen responder's medical status is not life threatening, the responder should be left in his or her suit and transported to the decon corridor and decontaminated in the suit, then treated upon exiting decon. The use of advanced life support (ALS) for patients without life-threatening illness or injury should be cautioned, as the potential for secondary contamination exists.

Responder Rescue Techniques

Hazmat responders working in CPC who collapse in the hot zone present significant logistical problems for potential rescuers. Drills conducted by the Jefferson County, KY, Emergency Medical Service's Disaster Response Team found many potential problems involving responder rescue.

Level A and Encapsulating B suits leave virtually no handhold for rescuers to grab, and the suit most likely will be inflated by the SCBA exhaust air, complicating the rescue. The presence of the SCBA will influence the method of responder removal. Backpack-style SCBA will not allow for the responder to be placed in a supine, or face-up, position. If the SCBA has older, flexible low-pressure hose from a waist-mounted regulator, the responder cannot be placed in a face-down position, nor can he or she lie down on the side to which the regulator is attached due to crimping and potential occlusion of the low-pressure hose. This limits the position in which the responder may be carried. Hazmat teams should experiment with their SCBA to determine any restrictions on which way a responder must be carried while wearing SCBA.

The method of removal from the hot zone will most likely entail the use of some form of device to assist the rescuers. The drills performed by Jefferson County EMS showed great difficulty in hand carrying a responder any distance.

Several devices were tried, with varying success. A long spine board proved to be almost too narrow with the additional body profile of the SCBA and CPC, and the high center of gravity made the board unstable to carry. Use of a military litter balanced the responder slightly better than the spine board but the litter soon showed signs of structural failure, possibly due to the added weight of the CPC. Using a wire basket litter proved to be easiest.

Each method brought out major logistical problems. The weight of the responder quickly exhausted the rescuers while exiting the hot zone, and frequent stops had to be made for rest. Also, in all cases either one rescuer had to lead the way out walking backwards with no visibility to his or her destination or both rescuers had to walk in a sidestep fashion, which left both rescuers with limited forward vision due to the orientation of the CPC facepieces toward the responder.

Jefferson County EMS developed a litter to overcome these obstacles. A standard wire basket litter was modified with wheels and handles, creating a wheelbarrow-type device that allows the rescuers to roll the fallen responder out of the hot zone.

Preparation Key To Success

While the collapse of a responder presents many potential problems for hazmat teams, training and the development of an action plan for such occurrences will better prepare the team both physically and emotionally for the event.

Hazmat teams should evaluate their resources and practice rescue procedures in a training situation to evaluate their practicality. Appropriate decisions based on past training experiences may help to reduce responder injuries and mortality during an incident.

Acknowledgements: Gene Carlson et al, Hazardous Materials for First Responders, Fire Protection Publications, Oklahoma State University, 1988; J. Veghte and J. Annis, Physiologic Field Evaluation of Hazardous Materials Field Ensembles, Federal Emergency Management Agency, 1991; Barry Yarbrough, M.D., and Roger Hubbard, M.D., "Heat Related Illnesses," Management of Wilderness and Environmental Emergencies, Paul Auerbach, M.D., C.V. Mosby Co., 1989; G. Noll, M. Hildebrand and J. Yvorra, Hazardous Materials Managing the Incident, Peake Productions Inc., 1988; R. Alexander, M.D., and H. Proctor, M.D., Advanced Trauma Life Support, American College of Surgeons, 1993; and L. Flint, M.D., et al, Healthcare Provider's Manual for Basic Life Support, American heart Association, 1990.

Kevin W. Johnson is a captain and supervising paramedic in the Jefferson County, KY, Emergency Medical Service. He is operations captain for its Disaster Response Team and Technical Rescue Unit and is a member of the Jefferson County Police Dive Rescue Team. Johnson is a flight paramedic for the University of Louisville Hospital STAT Flight and a captain in the Dixie Suburban Volunteer Fire Department. He holds an associate's degree in fire science and is an instructor in firefighting, advanced cardiac life support, basic trauma life support and trench rescue.